Concrete walls are typically constructed with large size planking or formwork. Using large size formwork is problematic in that the main load carrying wall must be recessed or include a keyway for the connection of partition or interior walls, stairs and intermediate floors. Conventionally, in order to bond a partition wall or staircase to a concrete structure, a connection groove was chiseled by hand using hammers. Such work is difficult, time consuming and expensive.
At first, this problem was avoided by encasing linear steel reinforcement bars in a strip of polystyrene plastic. The polystyrene plastic casing is secured to inside of the formwork with the bars extending through corresponding holes in the formwork wall. After the concrete solidifies, the formwork is removed over the bars and the polystyrene plastic is chipped away to create a keyway. This method is problematic because the formwork would generally be limited to a single use and the extensive amount of time required to remove the polystyrene plastic.
A solution to this problem, entailed bending the bars at a right angle and placing them in a hollow protective device secured to the formwork wall with a portion of the bar extending into the formwork area and another portion positioned within the hollow protective device. Thus, a connection groove is formed when the concrete is poured and the reinforcing steel rods are already concreted into the main wall. Therefore, the steel rods merely had to be bent to horizontal before the second wall was poured.
The present invention is directed to a device for housing steel reinforcements in areas where joints are made between first and subsequently poured concrete structures. Specifically, the devices of a type according to this invention are used in concrete construction to produce wall-to-wall or wall-to-slab junctions. They produce a continuous steel reinforcement in the joint region of two concrete structures with a T-shaped cross section.
Devices for protecting the steel reinforcements during the pouring of the first concrete structure are known. In the last few years, the use of industrially manufactured reinforcing rod holders which have already been equipped with the reinforcing rods before leaving the factory has increased considerably, and a large number of extremely varied reinforcing rod holders have been designed and used. During the course of ever wider applications and ever greater attempts at efficiency, it has become important to rapidly remove the protective portion of the rod holders to facilitate connection of the second wall.
It has also become important to safely remove the protective portion of the rod holders. Conventional protective devices are formed of sheet metal or expanded metal which, when being removed, often cuts or injures the remover. This has given rise to an increase in workman's compensation claims.
Attempts have been made to solve this problem by constructing the protective portion with a vacuum formed thin polymeric material. However, the thin protective portion tends to collapse when the concrete is poured, thereby distorting the keyway. Therefore, the keyway has to be hand chiseled to its proper shape. Additionally, the protective portions formed from polymeric materials often break during removal and, therefore, involve additional work to remove. Since the vacuum formed protective portions are derived from a mold, the position of the holes for receiving the reinforcement bars is predetermined and inflexible. Thus, the spacing of the reinforcement bars cannot be modified at the job site.
The present invention overcomes many of the disadvantages inherent in the above-described protective devices by providing a protective device which can be rapidly and safely removed from the main wall after it has solidified. Moreover, the protective device of the present invention is versatile in that the bars can be positioned within the device in any arrangement or spacing. Consequently, the protective device of the present invention increases job site safety and saves considerable time and money at the job site by reducing the time necessary to build concrete structures.